Shop Exhaust Mufflers Mufflers OEM Replacement
Big Twin Flathead / Knucklehead / Panhead

Big Twin Flathead / Knucklehead / Panhead

The Gasbox 1930 Twin Tube Mufflers
The Gasbox 1930 Twin Tube Mufflers
Top quality reproduction of the distinctive Twin Tube muffler as originally used on 1930 V-model Big Twins. Complete with its two clamps.
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The GasBox 1934 Upsweep Mufflers
The GasBox 1934 Upsweep Mufflers
Nice reproduction of the 1934 only muffler with upswept tail section. Custom use on other models is possible provided they have the correct headpipe diameter.
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The GasBox 1939 CHP Upsweep Mufflers
The GasBox 1939 CHP Upsweep Mufflers
Authentic reproduction of the special muffler for the California Highway Patrol (CHP) as introduced in 1939, with upswept tail section and spot-welded seam construction. Designed for rigid frame Big Twins for which a special hanger bracket is available, too, but can be Custom fitted to most models with 1-3/4" pipes.
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The GasBox Fishtail Mufflers
The GasBox Fishtail Mufflers
Top quality reproduction of the fishtail muffler as originally used on Big Twins 1935-1940. The E/U version has the Y-pipe integral with the fishtail muffler.
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The GasBox Fishtail Seamed Mufflers
The GasBox Fishtail Seamed Mufflers
Very authentic reproductions of the original mufflers with correct details like the patent stamp, spot-welded bottom seam, end cap beadings and pipe saddles. These are very hard to tell from the factory equipment and accepted by the AMCA on restored motorcycles.
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The GasBox Rocket Fin Seamed Mufflers
The GasBox Rocket Fin Seamed Mufflers
Very authentic reproductions of the original mufflers with correct details like the spot-welded bottom seam. These are very hard to tell from the factory equipment and accepted by the AMCA on restored motorcycles.
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Cigar Style Mufflers
Cigar Style Mufflers
The legendary »Cigar« muffler was standard equipment on all Big Twin models 1950-1964. This reproduction features exact dimensions as the original counterpart.
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Rocket Fishtail Mufflers
Rocket Fishtail Mufflers
Reproduction of the original Fishtail muffler used on Big Twins from 1961–1966. Moderate exhaust note. Perfect for restaurations.
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Original replacement mufflers for Knucklehead, Panhead and Big Twin Flathead

The big twins with OHV and SV engines have a pipe diameter of 1-3/4 " and used the same mufflers from 1937 onwards. Our original replacement silencers fit all the models mentioned, even though each model and year group always had its own style. In addition to use them as accurate original replacements, custom applications are also conceivable by mixing different model years and types. The manufacturer of our detailed quality reproductions is mainly The GasBox, a company that has earned an excellent reputation.

Have any questions?

Our service team will be glad to help out: Mondays - Thursdays 08:00-17:00 CET, Fridays 08:00-16:00 CET, Phone: +49 / 931 250 61 16, eMail: service@wwag.com